HD Pentax-DA AF Rear Converter 1.4x AW


bforbes

Link Posted 20/01/2015 - 21:05
From the IQ I've seen you be able to crop the 300+1.4 image as you would the 300 on it's own. Hope that answer your question
Barrie
Too Old To Die Young

http://www.pentaxphotogallery.com/artists/barrieforbes
https://www.flickr.com/photos/189482630@N03/

mille19

Link Posted 20/01/2015 - 21:09
NeilP wrote:

For those with DA*300mm and a K-3, how does the image quality with DA*300mm on the HD Pentax-DA AF Rear Converter 1.4x AW on compare to just cropping to the same field of view on just the DA*300mm on its own?

The image quality with the 1.4AW converter is excellent, I've found the 1.4AW a great help for birding, here's a few examples all with K3 and DA*300mm with converter.
The Blue Tit and Wren have both been cropped, the Blackbird hasn't.








Last Edited by mille19 on 20/01/2015 - 21:11

50mpCMOS

Link Posted 20/01/2015 - 23:38
Would be interesting to see a few side by side comparisons with different lenses; especially other weather resistant lenses; given that the two main "edges" the teleconverter has is the Pentax label and the weather resistance of the device.

For instance in comparison; any lens without teleconverter on maximum settings; such as a Pentax K3 on full 24mp raw+jpeg, best possible settings. Then with the teleconverter as compared to cropped in to a similar range/distance.

Technically the teleconverter could win on single focal length lenses, but on most zoom lenses the crop factor might very well have the edge

johnriley

Link Posted 20/01/2015 - 23:46
Using the 55-300mm I'm quite certain it's better to use the converter than crop.

I'm expecting it to be excellent with the 100mm Macro lens, but I haven't got round to testing that out yet.
Best regards, John

Algernon

Link Posted 21/01/2015 - 09:49
You can also crop a TC shot. This is the 55-300 DA + Jessops 1.7x TC cropped to about half the frame from a JPG.

K-5 Handheld




The full frame




--
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Last Edited by Algernon on 21/01/2015 - 09:55

geordie01

Link Posted 22/01/2015 - 11:42
Nowt wrong with that Algi looks as good as the Pentax converter for a lot less dosh!!
I think I will stick with the Tammy 1.5 and the Pentax af 1.7.

widezu69

Link Posted 23/01/2015 - 18:57
Anyone tried it on Sigma lenses? How does it fair with HSM?

bforbes

Link Posted 23/01/2015 - 19:01
A very quick play on a Sigma 150-500 shows it operates. no idea about IQ
Barrie
Too Old To Die Young

http://www.pentaxphotogallery.com/artists/barrieforbes
https://www.flickr.com/photos/189482630@N03/

50mpCMOS

Link Posted 23/01/2015 - 19:11
Quote:
Anyone tried it on Sigma lenses? How does it fair with HSM?

My favorite lens combination to use this version of teleconverter with would be the non hsm Sigma 300mm f2.8. The Pentax 1.4 WR teleconverter does indeed work with every literal variation of Sigma hsm lenses, but... As with ANY lens the teleconverter is attached to; the better the aperture the better the focusing ability.

The teleconverter combination does work AS WELL with the following Sigma hsm variations...

1. Sigma 50-500; at the most extreme telephoto end due to the aperture, but easily corrected if zooming out a bit or with a bit of focus hunting
2. Sigma 150-500; same issue as above
3. Sigma 18-300; same as above

But try to figure out this math... Using either the teleconverter or not... That focusing still works better using Sigma f6.3 (again, teleconverter or not) than Pentax glass at f5.6.

Proven case in point... Those Sigma lenses mentioned above (all Sigma hsm) using the minimum aperture at f6.3, versus Pentax glass such as the Pentax 16-85 or even the Pentax 18-135... The Sigma glass wins. Do not know why, do not know how

Algernon

Link Posted 23/01/2015 - 19:27
bforbes wrote:
A very quick play on a Sigma 150-500 shows it operates. no idea about IQ

The HSM/SR lens works well with the Jessop 1.7x. Holding it steady is the hardest part.

--
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi

bforbes

Link Posted 23/01/2015 - 20:48
Algernon wrote:
bforbes wrote:
A very quick play on a Sigma 150-500 shows it operates. no idea about IQ

The HSM/SR lens works well with the Jessop 1.7x. Holding it steady is the hardest part.

--

Sorry, I was referring to the Pentax 1.4X
Barrie
Too Old To Die Young

http://www.pentaxphotogallery.com/artists/barrieforbes
https://www.flickr.com/photos/189482630@N03/
Last Edited by bforbes on 23/01/2015 - 20:49

Mike-P

Link Posted 23/01/2015 - 21:03
I certainly wouldn't rely on the autofocus when using the 1.4x on any HSM lens, it's very hit and miss ... it's better on Pentax SDM. Also it's non reporting on HSM so the Exif will be wrong as will the focal length (for SR) and aperture.

Tried on 50-150mm f2.8, 70-200mm f2.8 OS and 50-500mm OS.
. My Flickr
Last Edited by Mike-P on 23/01/2015 - 21:04

NeilP

Link Posted 23/01/2015 - 23:28
Thanks for responses folks.

I already have the Pentax 1.7x convertor but find it can soften the images a bit, and other times I can see any difference, so I rarely use it now. Anyone got both and compared them?
UK Wildlife blog ----- UK Wildlife Facebook page ----- UK wildlife Twitter

bforbes

Link Posted 23/01/2015 - 23:29
1.4 by a mile
Barrie
Too Old To Die Young

http://www.pentaxphotogallery.com/artists/barrieforbes
https://www.flickr.com/photos/189482630@N03/

carmagw

Link Posted 24/01/2015 - 10:59
NeilP wrote:

I already have the Pentax 1.7x convertor but find it can soften the images a bit, and other times I can see any difference, so I rarely use it now. Anyone got both and compared them?

I used to have the Pentax 1.7x but like you I found my copy softened the images so I preferred to crop. I have since got rid of the 1.7. Other people have had far better results with the 1.7 though so it may be variations in the quality of them. I also used to have the Tamron 1.4x but again was not happy with the image quality.

Having got the Pentax 1.4 I have no problems with it (speed of SDM autofocus is another issue), pretty much attached to my DA*300 permanently at the moment. The kingfisher pics in my gallery are taken with it and cropped to roughly 50% of original. For me its the ideal partner for the DA*300.

Regards

George
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